Anteroposterior stability after posterior cruciate-retaining total knee arthroplasty.

PURPOSE: A functional posterior cruciate ligament (PCL) is important for the knee stability after PCL-retaining total knee arthroplasty (TKA). The objectives of this study were to determine the anteroposterior (AP) displacement of the knee after a mobile- or fixed-bearing PCL-retaining TKA operated with a ligament-balancing technique and the correlation of AP stability with the clinical outcome. METHODS: The AP displacement of 160 TKAs in 143 patients was measured pre- and intra-operatively, and the results were compared to the AP displacement measured 4 years post-surgery. RESULTS: The change in AP displacement from intra-operative measurement to follow-up at the 25° measuring point was -1.2 mm; at 90°, it was -0.2 mm. Mobile bearings showed significantly greater AP displacement than fixed bearings. Older patients, male patients and patients receiving a fixed prosthesis had lower post-operative laxity compared with the overall population. CONCLUSIONS: The small change in AP displacement indicates that the PCL remains functional over time. In our study, we could not find any correlation between knee AP stability and clinical outcome, including passive flexion, Knee Society Score or Visual Analogue Scale of pain and satisfaction.

Unicondylar knee replacement with a new tensioner device: clinical results of a multicentre study on 168 cases.

INTRODUCTION: Ligament balancing is an established surgical technique in total knee arthroplasty with good clinical results. A similar technique for unicondylar knee arthroplasty was developed. The aim of this study was to asses the outcomes of a unicondylar knee replacement implanted with a ligament tensor. MATERIALS AND METHODS: A prospective multicentre study of 168 medial compartment unicondylar knee prosthesis with a minimum follow-up of 2 years. Clinically, the knee society score was recorded. For subjective assessment, the visual analogue scale (VAS) for pain and satisfaction was used. Radiographic analysis was performed to determine radiolucent lines. The surgical technique was based on a ligament-orientated procedure. With this technique, the femoral orientation, flexion/extension gaps and limb alignment is determined with a unique ligament tensor. RESULTS: The total KSS increased from 110.9 +/- 27.5 points preoperative to 176.5 +/- 21.1 points after 24 months. VAS for pain decreased from 6.0 +/- 1.9 preoperative to 2.8 +/- 1.7 after 24 months. VAS for satisfaction increased in the same period from 4.3 +/- 1.9 to 8.9 +/- 1.7. Four tibia implants had thin continuous radiolucent lines. Nine adverse events are reported. One patient died of unrelated causes. Five polyethylene inlays dislocated, one of five dislocated due to a fall. Three unicondylar knee prostheses were revised to a total knee arthroplasty, one because of undiagnosed pain, one for infection and one for femoral component malalignment. CONCLUSION: We have demonstrated the efficacy of a tension-controlled ligament-balanced surgical technique for unicompartmental knee prosthesis that gives satisfying and reproducible short-term results.

Gradient-based optimization with B-splines on sparse grids for solving forward-dynamics simulations of three-dimensional, continuum-mechanical musculoskeletal system models.

Investigating the interplay between muscular activity and motion is the basis to improve our understanding of healthy or diseased musculoskeletal systems. To be able to analyze the musculoskeletal systems, computational models are used. Albeit some severe modeling assumptions, almost all existing musculoskeletal system simulations appeal to multibody simulation frameworks. Although continuum-mechanical musculoskeletal system models can compensate for some of these limitations, they are essentially not considered because of their computational complexity and cost. The proposed framework is the first activation-driven musculoskeletal system model, in which the exerted skeletal muscle forces are computed using 3-dimensional, continuum-mechanical skeletal muscle models and in which muscle activations are determined based on a constraint optimization problem. Numerical feasibility is achieved by computing sparse grid surrogates with hierarchical B-splines, and adaptive sparse grid refinement further reduces the computational effort. The choice of B-splines allows the use of all existing gradient-based optimization techniques without further numerical approximation. This paper demonstrates that the resulting surrogates have low relative errors (less than 0.76%) and can be used within forward simulations that are subject to constraint optimization. To demonstrate this, we set up several different test scenarios in which an upper limb model consisting of the elbow joint, the biceps and triceps brachii, and an external load is subjected to different optimization criteria. Even though this novel method has only been demonstrated for a 2-muscle system, it can easily be extended to musculoskeletal systems with 3 or more muscles.

[High-resolution T1-weighted MR-lymphography of inguinal lymph nodes after interstitial application of Gadomer-17 in animal experiments]. / Hochauflösende T1-gewichtete MR-Lymphographie inguinaler Lymphknoten nach interstitieller Applikation von Gadomer-17 im Tierexperiment.

PURPOSE: To evaluate the microstructural anatomy of inguinal lymph nodes in pigs after interstitial MR-lymphography with the dendritic contrast agent Gadomer-17. MATERIAL AND METHODS: High-resolution T1-weighted MR-lymphography was performed in inguinal lymph nodes of 10 domestic pigs (39 - 46 kg) after subcutaneous injection of 10 mumol/kg body weight Gadomer-17 in the hind legs of the animals. A 1.5T MR scanner and a ring-shaped surface coil were used. Two different high-resolution gradient-echo sequences with additionally reconstructed maximum-intensity projections were evaluated in a total of 20 lymph nodes. The high-resolution MR-findings were correlated with the histologic sections of the excised inguinal lymph nodes. RESULTS: Coronal T1-weighted 3D gradient-echo images (TR = 20 msec, TE = 6.1 - 8.3 msec, FA = 20 degrees ) with a slice thickness of 1 mm, a field-of-view of 120 mm and a matrix size of 256 x 256 (reconstructed to 1024 x 1024 voxels) yielding a reconstructed in-plane resolution of 117 x 117 microm (2) were best suited for the high-resolution MR lymphography of inguinal lymph nodes and enabled the differentiation of the hyperintense lymph node sinuses and hypointense lymphoid parenchyma of each lymph node (100 %). Even dilated lymphatic vessels evident in the histologic specimen were best demonstrated on the MIP images. CONCLUSION: High-resolution interstitial MR lymphography with Gadomer-17 allows the visualization of different tissue compartments of inguinal lymph nodes. This new technique is feasible on a routine 1.5T scanner and may offer potential for the detection of micrometastases in lymph nodes of cancer patients.

Disseminated Mycobacterium avium complex disease in the Swiss HIV Cohort Study: increasing incidence, unchanged prognosis.

OBJECTIVES: Disseminated disease due to Mycobacterium avium complex (MAC) bacteria is thought to occur less frequently in Europe than in the USA. This study investigated time trends in the occurrence of, and survival with, disseminated MAC disease in the Swiss HIV Cohort Study (SHCS). DESIGN, SETTING AND PARTICIPANTS: The SHCS participants who were free of disseminated MAC disease at registration were stratified by calendar period (1987-1989, 1990-1992, 1993-1995) in which the first recorded CD4 count was 0-49, 50-99, or 100-199 x 10(6)/l. Kaplan-Meier estimates of the probability of developing and surviving disseminated MAC disease were calculated for these nine independent groups. Multivariate analyses were performed using Cox proportional hazards regression. RESULTS: The analysis was based on 6052 participants enrolled between January 1987 and December 1995 and 202 incident episodes of disseminated MAC disease recorded during a mean follow-up time of 3.5 years. The cumulative probability of MAC disease at 2 years in individuals with CD4 counts of 0-49 x 10(6)/l in 1987-1989 was 9.8% [95% confidence interval (CI) 4.4-15.2%], increasing to 29.8% (95% CI, 20.8-38.8%) in 1993-1995. Amongst those with CD4 counts from 50-99 x 10(6)/l these probabilities were 11.9% (95% CI, 5.9-17.8%), and 21.6% (95% CI, 13.9-29.2%), respectively. After adjusting for CD4 count the relative hazard of developing disseminated MAC disease in 1993-1995, compared with 1987-1989, was 1.37 (95% CI, 0.92-2.04). Median survival following diagnosis was 7.9 months with no improvement over time. CONCLUSIONS: The incidence of disseminated MAC disease among SHCS participants has increased over time. More profound levels of immunosuppression amongst recent study entrants were found to explain this. When compared with US cohorts studied over the same calendar period the incidence of disseminated MAC disease in the SHCS appears to be lower. These findings are consistent with a secular effect of a more mature HIV epidemic in the US but direct comparison between the SHCS and a similar prospective cohort in the US should be undertaken to clarify this issue.

Cost effectiveness of highly active antiretroviral therapy in HIV-infected patients. Swiss HIV Cohort Study.

BACKGROUND: Highly active antiretroviral therapy (HAART) has become the most important strategy for treating HIV infection in developed countries; however, access to HAART might vary under different funding policies. The Swiss health care system provides unrestricted access to HAART for all patients who need these newer combination therapies. This study investigated the impact of this funding policy on the society and health care system. METHODS: A cost-effectiveness analysis with natural history data and productivity estimates was based on the Swiss HIV Cohort Study. A random sample of patient charts was used to estimate health care costs. In addition to a base-case scenario, a pessimistic and an optimistic scenario of natural disease history was developed. Costs were expressed in 1997 Swiss francs (100 CHF correspond to about US$67) and effects as projected years of life gained. RESULTS: In the analysis limited to health care costs, on the basis of projected survival in each scenario, the cost-effectiveness ratio was 33,000 CHF (base case), 14,000 CHF (optimistic), and 45,000 CHF (pessimistic) per year of life gained. When changes in productivity were included, cost savings occurred in the base-case and optimistic scenarios. The cost-effectiveness ratio was 11,000 CHF per year of life gained in the pessimistic scenario. CONCLUSIONS: HAART increases expected survival and health care costs. However, when productivity gains are included, society will probably save costs or pay a low price for substantial health benefits. The study provides strong arguments, from a societal perspective, to continue the current policy of providing unrestricted access to HAART in Switzerland. The presented results also suggest that this policy could be of interest for other developed countries. Decision makers in developed countries where access to HAART is limited should re-evaluate their policy for the benefit of the society at large.

Triglyceride as a risk factor for ischaemic heart disease in British men: effect of adjusting for measurement error.

OBJECTIVE: To assess the influence of differential precision in the measurement of the correlated variables total cholesterol and high density lipoprotein (HDL) cholesterol on the estimates of the risk of ischaemic heart disease (IHD) associated with plasma triglyceride levels. DESIGN, SETTING AND PARTICIPANTS: The Caerphilly Heart Disease Study (CHDS), a prospective cohort study of 2512 middle-aged men living in the town of Caerphilly, south Wales, UK. The results from two sub-studies were used to estimate the degree of measurement imprecision (laboratory error and within-person variation) in triglycerides, total cholesterol and HDL cholesterol. MAIN OUTCOME MEASURES: Multivariable risk estimates for major IHD calculated from logistic regression analysis, adjusted and not adjusted for measurement imprecision. Major IHD events were defined as death from IHD, clinical non-fatal myocardial infarction or electrocardiographic myocardial infarction. RESULTS: There were 261 men with major IHD events during follow-up. In age-adjusted analyses, taking measurement imprecision into account strengthened associations with IHD for all lipid factors. The odds ratio (OR) for one S.D. increase in triglycerides, ignoring measurement imprecision, was 1.36 (95% confidence interval [95% CI] 1.20-1.55) but 1.57 (95% CI 1.30-1.89) when taking imprecision into account. The standardised odds ratio for triglycerides adjusted for measurement imprecision and the two other lipid factors was 1.35 (95% CI 1.09-1.69). In this model, the triglyceride level showed a stronger association than total cholesterol (OR 1.28; 95% CI 1.05-1.56) and HDL cholesterol (OR for one S.D. decrease 1.20; 95% CI 0.97-1.49). When adding fasting blood glucose and diastolic blood pressure, however, the effect of triglycerides was reduced and ceased to be statistically significant (OR 1.19; 95% CI 0.95-1.49). This was further attenuated upon inclusion of body mass index, smoking status and history of pre-existing IHD. Total cholesterol remained a statistically significant (P < 0.05) risk factor in all models. CONCLUSIONS: In contrast to other cohort studies, triglyceride concentration in the CHDS shows an association with the risk of IHD which is independent of total and HDL cholesterol. This effect was pronounced after adjustment for measurement imprecision. It was reduced, however, when adjusted for other factors. While hypertriglyceridaemia may exert an influence independent of other lipid factors, insulin resistance is probably the underlying metabolic disturbance.

[Interstitial T1-weighted MR lymphography with use of the dendritic contrast agent Gadomer-17 in pigs]. / Interstitielle T1-gewichtete MR-Lymphographie mit dem polymeren Kontrastmittel Gadomer-17 im Tierexperiment.

PURPOSE: To investigate the enhancement of regional lymph nodes, lymph vessels and the thoracic duct after subcutaneous administration of the dendritic contrast agent Gadomer-17. MATERIALS AND METHODS: Interstitial T(1)-weighted MR lymphography was performed in 15 domestic pigs in a 1.5 T MR scanner using the body coil. The contrast agent was injected subcutaneously at a dose of 2.5, 10 and 20 micromol gadolinium/kg/bw (1.4 - 2.3 ml) in the hind legs of 5 pigs, respectively. T(1)-weighted coronal 3D-gradient-echo images were obtained 1 to 150 minutes and 24 hours after contrast material injection. RESULTS: Inguinal lymph nodes, iliac lymph nodes and lymph vessels showed peak enhancement within 10 minutes after subcutaneous administration of the contrast agent. The enhancement of the lymphatic system decreased slowly until 150 minutes post injection. The time-response study, which was performed for inguinal and iliac lymph nodes, revealed the best lymphographic effect for Gadomer-17 at a dose of 10 micromol gadolinium/kg/bw. At this dose the paraaortic lymph nodes and the thoracic duct were also best visualized. CONCLUSION: Interstitial administration of the evaluated dendritic contrast agent Gadomer-17 is highly efficient for the performance of T(1)-weighted MR lymphography in regional lymph nodes, lymph vessels and the thoracic duct.

[Interstitial T1-weighted MR lymph fistulography with Gadomer-17 in an experimental animal model]. / Interstitielle T1-gewichtete MR-Lymphfistulographie mittels Gadomer-17 im Tierexperiment.

PURPOSE: To visualize and localize fistulas of the thoracic duct with interstitial T 1 -weighted MR lymphography using Gadomer-17. MATERIALS AND METHODS: In 10 domestic pigs, leaks of the thoracic duct were created surgically or interventional-radiologically. The lymphatic leakage was located within the abdominal portion of the thoracic duct in 5 pigs, within the thoracic portion of the thoracic duct in 3 pigs, and in both, abdominal and thoracic portions of the thoracic duct, in 2 pigs. Subsequently, 10 micro mol/kg KG Gadomer-17 (1.5-1.8 ml) was administered interstitially in both hind legs of the animals. MR lymphography was performed with a 1.5 T MR unit using two different 3D gradient echo sequences before and 10 - 90 minutes after administration of contrast material. RESULTS: Leaks within the abdominal portion of the thoracic duct were directly visible as opacified fistulas. Indirect signs of active lymphatic fistulas were increasing extravasations of contrast material and free abdominal fluid. The 3D gradient echo sequence with the highest planar resolution (TR = 8,7 - 8,8 ms, TE = 4,2 - 4,3 ms, FA = 40 degrees, matrix size = 327 x 512) was best suited for distinct delineation of the lymphatic system and detailed demonstration of the thoracic duct fistulas. Intrathoracic leaks could not be demonstrated by MR lymphography due to reduced lymphatic flow or extravasated contrast medium at the abdominal puncture site. CONCLUSION: Interstitial MR lymphography with Gadomer-17 allows sensitive detection and localization of abdominally located leaks of the thoracic duct.

Systematic validation of disease models for pharmacoeconomic evaluations. Swiss HIV Cohort Study.

Pharmacoeconomic evaluations are often based on computer models which simulate the course of disease with and without medical interventions. The purpose of this study is to propose and illustrate a rigorous approach for validating such disease models. For illustrative purposes, we applied this approach to a computer-based model we developed to mimic the history of HIV-infected subjects at the greatest risk for Mycobacterium avium complex (MAC) infection in Switzerland. The drugs included as a prophylactic intervention against MAC infection were azithromycin and clarithromycin. We used a homogenous Markov chain to describe the progression of an HIV-infected patient through six MAC-free states, one MAC state, and death. Probability estimates were extracted from the Swiss HIV Cohort Study database (1993-95) and randomized controlled trials. The model was validated testing for (1) technical validity (2) predictive validity (3) face validity and (4) modelling process validity. Sensitivity analysis and independent model implementation in DATA (PPS) and self-written Fortran 90 code (BAC) assured technical validity. Agreement between modelled and observed MAC incidence confirmed predictive validity. Modelled MAC prophylaxis at different starting conditions affirmed face validity. Published articles by other authors supported modelling process validity. The proposed validation procedure is a useful approach to improve the validity of the model.

A mortality study of lung cancer among swiss professional drivers: accounting for the smoking related fraction by a multivariate approach.

The mortality due to lung cancer among 'chauffeurs', who have a presumably long-term exposure to diesel exhaust fumes, was analysed. As controls, men in industrial occupations of similar socio-economic status were selected. Cases were drawn from the Swiss mortality register for the years 1979-1983. Person-years were obtained using data from the 1980 census records. These two data files were combined by occupation, age class and socio-economic status. Age adjusted incidence rates were calculated applying Poisson regression. To control for tobacco related lung cancer mortality an indirect adjustment was undertaken. Using information about the smoking habits of the people in the occupations under study, smoking-attributable lung cancer mortality was accounted for by incorporating Axelson's technique into multivariate regression modeling. The mortality ratio for lung cancer for chauffeurs with respect to the controls was 2.27, which is significantly in excess of 1:95% CI (1.99, 2.58). Other tobacco related diagnoses such as bladder cancer, esophageal cancer and ischemic heart diseases showed excess risks as well. After accounting for smoking, a slight but significant increase in lung cancer mortality remained among chauffeurs (mortality ratio 1.48, 95% CI: 1.30, 1.68). In summary, the present results do support the hypothesis that diesel exhaust is a significant cause of lung cancer.

The results of the titanium-coated RM acetabular component at 20 years: a long-term follow-up of an uncemented primary total hip replacement.

In a prospective study, 93 unselected consecutive uncemented hip arthroplasties were performed in 80 patients using the titanium-coated RM acetabular component and the CLS femoral component. The mean age of the patients at operation was 52 years (28 to 81). None were lost to follow-up. In the 23 patients who had died (26 hips) only one acetabular component had been revised. In the 57 living patients (67 hips), 13 such revisions had been performed. Of the 14 revisions, seven were for osteolysis, five for loosening and two for infection. Survival analysis of this implant showed a total probability of survival of 83% (95% confidence interval 73 to 90), with all revisions as the endpoint, and a probability of 94% (95% confidence interval 87 to 98) with revision for aseptic loosening as the endpoint, indicating reliable long-term fixation of the titanium-coated RM acetabular component.

Does total knee joint replacement with the soft tissue balancing surgical technique maintain the natural joint line?

INTRODUCTION: The outcomes of 106 total knee arthroplasties implanted using a soft tissue balancing surgical technique at one surgical centre were used to assess the accuracy maintaining the knee's original joint line (JL). The aim of the study was to determine whether there is a shift of the presumed joint line after surgery. MATERIALS AND METHODS: Preoperative and post-operative radiographs were compared to determine any changes in the articulation height. The preoperative distance of the fibular head to the natural joint line was measured and compared with the post-operative measurement of the fibular head to the femoral articulation line (measured on the radiograph and defined as Rxmm). Based on the actual medio-lateral dimension of the tibial metal back, the measured difference (RXmm) could be converted into true distances (in mm). The Blackburn-Peel index was assessed as an additional outcome prior to and following surgery. RESULTS: Preoperatively, the average distance from the fibular head to the joint line was 15.1 Rxmm (SD 4.3) while the post-surgical distance was 15.5 Rxmm (SD 5.6). The average deviation of the post-surgical JL in relation to the original JL amounted to 0.4 Rxmm (SD 3.7). The average deviation of the joint line converted into the true distance was -0.3 mm (with a range of -5.9 mm in distal direction to + 8.3 mm in the proximal direction). Valgus position appeared to generate rather a shift in proximal direction whereas varus deformity favours a shift in distal direction. Seven patients exhibited a deviation of more than 5 mm in either the distal or proximal direction. All of the patients of this subgroup had a preoperative anatomical abnormality including a severe malalignment, serious bone destruction or had previously undergone a high tibial osteotomy. CONCLUSION: An exact reconstruction of the natural Joint Line is achievable when using the described soft tissue balancing surgical technique with the posterior cruciate ligament (PCL) retaining prosthesis design used in this series.

[Preissler endoscopic carpal ligament release. Experiences from 1,000 operations]. / Die endoskopische Karpalbandspaltung nach Preissler. Erfahrungen aus 1,000 Operationen.

To reduce the postoperative morbidity different methods of endoscopic carpal tunnel release have been developed since 1989. We report our results and experiences with the method described by Preissler. Since its introduction in our clinic 1995, 1,000 patients have been operated until now. Out of 477 with an electrophysiological examination, 396 patients (83%) showed no symptoms. In three cases it was necessary to change to an open approach during operation, there were no other intraoperative complications. To evaluate our results we sent a questionnaire to 32 of our patients that were operated on one hand with an open technique and on the other hand with the endoscopic technique of Preissler. The results demonstrated that the endoscopic method was significantly better. From our experience endoscopic technique for carpal tunnel release Preissler's is a safe, well accepted, easy for learning and cheap alternative to the open procedure.

Leukemia, brain tumors, and exposure to extremely low frequency electromagnetic fields in Swiss railway employees.

Railway engineers provide excellent opportunities for studying the relation between exposure to extremely low frequency magnetic fields and leukemia or brain tumors. In a cohort study of Swiss railway personnel with 2.7 x 10(5) person-years of follow-up (1972--1993), the authors compared occupations with high average exposures (line engineers: 25.9 microT) to those with medium and low exposures (station masters: 1 microT). The mortality rate ratio for leukemia was 2.4 (95% confidence interval (CI): 1.0, 6.1) among line engineers (reference category: station masters). The mortality rate ratio for brain tumors was 1.0 (95% CI: 0.2, 4.6) among line engineers and 5.1 (95% CI: 1.2, 21.2) among shunting yard engineers (compared with station masters). Two exposure characteristics were evaluated: cumulative exposure in microT-years and years spent under exposure to magnetic fields of > or =10 microT. There was a significant increase in leukemia mortality of 0.9% (95% CI: 0.2, 1.7) per microT-year of cumulative exposure to extremely low frequency magnetic fields. The increase by years spent under exposure of > or =10 microT was even stronger: 62% per year (95% CI: 15, 129). Brain cancer risk did not show a dose-response relation. This study contributes to the evidence for a link between heavy exposure to extremely low frequency magnetic fields and leukemia. Its strengths include reliable measurements and reliable historical reconstruction of exposures.

Effects of exposure to 16.7 Hz magnetic fields on urinary 6-hydroxymelatonin sulfate excretion of Swiss railway workers.

The aim of our study was to examine the effects of 16.7 Hz electromagnetic-field exposure on pineal melatonin production in healthy humans. The study was based on comparing urinary 6-hydroxymelatonin sulfate (6-OHMS) levels of 108 male railway workers between leisure periods and days following the start of service on electrically powered engines (66 engineers) or working beneath transmission lines (42 railway employees such as train attendants and station managers; controls). A repeated measures design was used, i.e., each volunteer served as his own control. The exposure averaged 20 muTesla in the most exposed workers and around 1 muTesla in the least exposed. Apart from magnetic exposure the workers were subject to a shift work schedule with daily advances between 15 min and 1 hr. Melatonin was assessed by sampling urinary 6-OHMS both in the morning and the early evening. Evening 6-OHMS values appeared to be lowered by a factor of 0.81 (95%CI: 0.73-0.90) during work days compared to leisure days among engine drivers, but not in the controls. The lowering was not confined to certain types of shift work such as early, normal, or late shifts. During subsequent leisure periods evening values recovered significantly, mean ratio = 1.27 (95%CI: 1.03-1.56), i.e., the effects appeared to be reversible. In contrast, morning 6-OHMS samples of engineers and controls did not differ much between work and leisure days. There was, however, a tendency for a rebound of morning values in a leisure period following a work period both for engineers and controls. The observed pattern appears to be in line with predictions of the "phase response curve." No evidence for a dose-response relation was found. The results support the hypothesis that 16.7 Hz magnetic fields alter 6-OHMS excretion in humans exposed to magnetic fields. An alternative explanation that cannot be excluded in this study is that the difference between engineers and controls is due to differential exposure to day light at work.

The fate of bilateral lower limb amputees in end-stage vascular disease.

Sixty-six patients with end-stage peripheral vascular disease who had undergone bilateral major amputation of the lower extremities in our institution during the 10-year period January 1980-December 1989 were reviewed. There were 46 males and 20 females with an age range from 34 to 91 years (mean 67.7 years). A 98.5% follow-up was achieved. Of these patients 25% underwent their second amputation in the first, 50% within the second and 75% within the third postoperative year, notwithstanding the fact that prior attempts at revascularisation had been performed in 62% of all patients. The 30-day hospital mortality was 4.5%. The initial level of amputation was metatarsal in 14.4%, below knee in 66.6%, through knee in 9.9% and above knee in 9.1%. Out of a total of 132 stumps 89 healed by primary intention. Following secondary revisions and amputations the final level of amputation was metatarsal in 7%, below knee in 49%, through knee in 14% and above knee in 30%. Survival rates were 62% after 2 years, 31% after 5 years, and 14% after 8 years. By this time all diabetics had died, while 33% of non-diabetics were still alive (p greater than 0.02). Age, sex and amputation level had no bearing upon survival rate. Forty-three patients (65.1%) were ambulatory after their first amputation, but following contralateral amputation barely more than half (23 patients) were able to walk. In the presence of bilateral stage IV disease it is highly important to rehabilitate the patient immediately following unilateral amputation before considering amputation of the contralateral limb, otherwise the patient will not become ambulatory.

[Identification of crystals in synovial fluid: joint-specific identification rate and correlation with clinical preliminary diagnosis]. / Kristallnachweis in der Synovialflüssigkeit: gelenkspezifische Nachweisfrequenz und Korrelation zur klinischen Verdachtsdiagnose.

The diagnostic clarification of joint effusions of unknown origin is a challenge to every primary-care physician. Important diagnostic procedures are arthrocentesis and analysis of the aspirated synovial fluid. Synovial fluid analysis frequently allows differentiation between harmless effusions due to osteoarthritis and crystal induced inflammation, or the more devastating septic arthritis. 4475 synovial fluids were evaluated retrospectively to calculate the identification rate of crystals compatible with calcium pyrophosphate dihydrate (CPPD) and monosodium urate monohydrate (MSUM). 40.8% (1827) of synovial fluids were taken from females and 59.2% (2648) from males. The frequency of crystal identification varied considerably: 13.2% CPPD crystal identification in females, 10.9% in males; MSUM was identified in 1.5% of females, and in 10.9% of males. The spectrum of joint involvement was nearly identical in CPPD and MSUM positive synovial fluids. Exceptions were the higher frequency of CPPD identification in shoulder joints (CCPD:MSUM = 15.6:1), the higher frequency of MSUM identification in the ankle (MSUM:CPPD = 15.6:1) and the first metatarsophalangeal joints (MSUM:CPPD = 8:1). Clinical suspicion correlated well with crystal identification in MSUM positive samples (60%), but was poor in CPPD positive samples (36%). The poor correlation between clinical suspicion and crystal identification in CPPD positive synovial fluids is explicable by the less characteristic clinical presentation of pyrophosphate arthropathy in contrast to classical gout. A high percentage of crystal identification was found in joints or periarticular swellings in which aspiration is difficult and therefore rare (e.g. tendon sheaths, first metatarsophalangeal and first metacarpophalangeal joints), underlining the importance of synovial fluid aspiration despite the difficulty of arthrocentesis.

[Accidental hypothermia in Switzerland (1980-1987)--case reports and prognostic factors]. / Akzidentelle Hypothermie in der Schweiz (1980-1987)--Kasuistik und prognostische Faktoren.

This retrospective study comprises 234 cases of accidental hypothermia (core temperature less than 35 degrees C) hospitalized in 95 Swiss clinics between 1980 and 1987. The most frequent accidents were alpine (n = 78) in origin, followed by cold exposure after injuries (n = 63) and suicide attempts (n = 43). Hypothermia was induced by cold air in 129 cases and by water in 47 cases. Patients were divided evenly between the degree of hypothermia: 75 mild (32-35 degrees C), 79 moderate (28-32 degrees C) and 66 severe (less than 28 degrees C). Among the survivors the coldest patient had a core temperature of 17.5 degrees C and the longest cardiac arrest with a favourable outcome lasted 4.75 hours. Out of the 234 patients 68 died (29%). We assessed all variables relative to outcome, in particular the mechanism of the accident, the mode of cooling, temperature, circulation, age and sex, underlying diseases, rewarming methods, medication and complications during the hospital course. All variables were tested in two multiple regression analysis models (retrospective model n = 181: prospective model n = 128) with regard to significance (p less than 0.05) and survival. Results are expressed with ODD's ratios (OR). The negative survival factors are asphyxia (OR 30), invasive rewarming methods (OR 20), slow rate of cooling (OR 10), asystole on arrival (OR 9), pulmonary edema or ARDS during hospitalization (OR 8), elevated serum potassium (OR 2/mmol/l) and age (OR 1.03/year). The positive survival factors are rapid cooling rate (OR 10), presence of ventricular fibrillation in cardiac arrest patients (OR 9) and presence of narcotics and/or alcohol during hypothermia (OR 5).(ABSTRACT TRUNCATED AT 250 WORDS)